1. Field of the Invention
The present invention relates to a method and an arrangement using a detector surface and a light source for determination of the level of two or more measurement points, a light beam being produced along a first direction, the light beam being deflected through 90° with respect to the first direction to a second direction, with the second direction being rotated through a rotation angle corresponding to the position of the measurement point about an axis which is formed by the first direction.
2. Description of Related Art
A method and an arrangement of the generic type described above are known from Japanese patent publications JP 2000-46551 and JP 2000-213937, respectively, with the beam direction of a laser being steered accurately in a desired azimuth rotation direction. For this purpose, the beam of a laser diode which is emitted vertically upwards is deflected through 90° by means of a pentagonal prism. The pentagonal prism rotates the laser beam in a plane at right angles to the emission direction. An encoder with a round encoder plate is used in order to determine the respective rotation angle of this rotation, and the rotation angle is evaluated via an encoder sensor. In order to determine the position of a measurement point in this way, its height z above a horizontal reference plane (for example, the rotation plane of the laser beam) must be determined by means of an additional measurement method, using cylindrical coordinates, and its radial distance from a vertical reference axis (for example, the emission axis of the laser) must be determined by means of a further measurement method.